Cod sursa(job #2211431)
Utilizator | Data | 10 iunie 2018 12:11:41 | |
---|---|---|---|
Problema | Aria | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.45 kb |
#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
ifstream in("aria.in");
ofstream out("aria.out");
struct vertex{
int x, y;
}a[100010];
double s;
int main(){
int n, i, j;
in >> n;
for(i = 1; i <= n; i++)
in >> a[i].x >> a[i].y;
a[n + 1] = a[1];
for(i = 1; i <= n; i++)
s += a[i].x * a[i + 1].y - a[i].y * a[i + 1].x;
out << fixed << setprecision(5) << s / 2;
return 0;
}